I can't render past frame 35!
If Blender is freezing and crashing while you're rendering, then the animation is doing something that demands more resources than Blender is able to give it.

Without being able to see the file, it's really hard to guess. There are a number of things that might be going on at frame 35. At that point, there are some keyframes. These keyframes might be related to something very complex going on. There might be a whole lot of objects introduced into the scene at that point, which would increase the RAM requirement. There might be some kind of feature introduced at that point, that Cycles isn't able to handle.

It looks like this scene might be trying to use Animation Nodes, which aren't supported in 2.70.

Generic solutions are few and far between, but one of them is upgrade Blender to the latest release (the one on Blender.org, not from the nightly builds). Don't try to solve anything else until you've upgraded.

The next thing you need to do is find out what NEW thing the scene is trying to do at frame 35.


Look in the Visual Sequence Editor to see if there's a new effect or strip that starts at frame 35.
Look in the Graph Editor and/or Dope Sheet to see if there are any animations that start on frame 35.
Look in the Compositor to see if there are any nodes that have keyframes. Maybe there's a compositing thing that starts at frame 35.
Look in the Console (Windows -> Toggle System Console) to see if it's giving you any error information that might help.
Look in the Info panel (blue circle with an 'i'; it looks like it's just a menu bar, but drag its border to make it bigger) to see if there are any errors there that might help.


On an unrelated note, if you've gotta deliver this to a client, you don't have time to solve this problem. You've run into this problem already. It's likely that you'll run into more problems with the same file, even if you solve this one. You need to dump this file and go find another solution.